How to fixed each column width in jgGrid ?

Question

colModel:[{name:'SalesNumber', index:'SalesNumber', key:true, width:150}, {name:'Customer', index:'Customer', width:150}, {name:'Title', index:'Title', width:150}, {name:'AssignedDate', index:'AssignedDate', width:100}, {name:'FollowUpDate', index:'FollowUpDate', width:100}, {name:'BusinessUnit', index:'BusinessUnit', width:100}, {name:'Step', index:'Step', width:100}],

you can see each column width is range between 100-150.There have 6 columns. I want to set each column have fixed width and scrollbar is appear when page load.

I have tried to set the width to 150 but when page load the columns not really 150 width and scrollbar no appear. But the 6 columns did not show the column text properly because the width not enough to display it ! how i do it ?!change any setting ?